Spin-Axis Stabilization of an Underactuated Flexible Spacecraft Using Two Reaction Wheels
- Paper number
IAC-08.C1.8.3
- Author
Dr. Fang Wang, China Academy of Space Technology (CAST), China
- Coauthor
Dr. Honghua Zhang, Beijing Institute of Control Engineering, China
- Coauthor
Prof. Pavel M. Trivailo, Royal Melbourne Institute of Technology (RMIT), Australia
- Year
2008
- Abstract
The underactuated spacecraft is characterized by the fact that the configuration of the actuators is incomplete, which indicates that the actuators can’t provide three independent control torques such as only two fly wheels available or thrusters with no more than two control torques. There are many researchers, such as Crouch, Brockett, Byrnes, Krishnan, Tsiotras, Morin, Samson, Fauske.et al. have worked on designing controllers for stabilizing the underactuated spacecraft. However, all of them considered only the rigid spacecraft, and the actuators were assumed to be jet thrusters. With the development of the space technology, more spacecraft are with large flexible solar array or other flexible attachments. The control torques acted on the spacecraft will not only influence the position and attitude but also induce the flexible oscillation which in turn influences the kinematics and control of the spacecraft. Therefore it’s necessary to study the attitude control problem of underactuated spacecraft with flexible components, which is the novelty of the paper. On the other hand, it is well known that with less than three momentum wheels the system is uncontrollable and only when the total angular momentum vector of the spacecraft is zero can the system be stabilized. In this note, the paper here only deals with the control of the spin-axis using reaction wheel, which is a problem of partial stability, i.e., stability with respect to part of the system’s states, and has practical meanings since one typical case is that when the axis of the spacecraft is the axis of a communications antenna, the line-of-sight of an onboard telescope or camera, etc., the relative rotation about the axis is irrelevant. Therefore, the contribution of the paper lies in the study of the spin-axis stabilization control for the underactuated flexible spacecraft using fly wheels. Without loss of generality, the flexible spacecraft is under two fly wheels with the third axis failed. The paper first constructs the mathematical model of the underactuated flexible spacecraft using Euler-Poisson form. Then the paper presents a detailed approach to analyze the control law by using the Lyapunov function method with the global asymptotic stability of the closed-loop system proved using the LaSalle’s theorem. The mathematical simulation results also show the effectiveness of the proposed controller. Further research involves cases when the underactuated flexible spacecraft is under disturbances and the inertia matrix is unknown or poorly known, of which the controller will become more complicated.
- Abstract document
- Manuscript document
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